Systems and methods for recovering hydrocarbons

ABSTRACT

A method for recovering hydrocarbons from an aqueous hydrocarbonaceous slurry comprises pumping a mixture of the slurry and an oxidizing agent through a conduit, wherein the conduit comprises a plurality of stationary interior projections defining a non-linear path through the conduit, and thereby agitating the mixture to release the hydrocarbons from the slurry; and separating the hydrocarbons from the slurry.

CLAIM OF PRIORITY

This patent application is a Continuation application of U.S. patentapplication Ser. No. 14/617,075, filed on Feb. 9, 2015, which is aDivisional application and claims the benefit of priority of U.S. patentapplication Ser. No. 13/782,073, filed on Mar. 1, 2013, which claims thebenefit of priority of U.S. Provisional Patent Application Ser. No.61/605,593, filed on Mar. 1, 2012, the benefit of priority of each ofwhich is claimed hereby, and which are incorporated by reference hereinin their entirety.

FIELD OF THE INVENTION

The present invention relates to hydrocarbons. More specifically, thepresent invention relates to systems and methods for recoveringhydrocarbons from a hydrocarbonaceous slurry.

BACKGROUND OF THE INVENTION

Methods for treating hydrocarbon-containing materials using an oxidizingagent are known. For example, U.S. Pat. Nos. 5,797,701, 5,928,522,6,096,227, and 6,251,290 describe methods that involve combining anaqueous slurry with an oxidizing agent, such as hydrogen peroxide,heating the resulting mixture to up to 80° C., and then agitating themixture to oxidize the hydrocarbons and facilitate their separation fromthe slurry. U.S. Pat. No. 6,951,248 describes a method for separatingoil from geological formations by application of an aqueous oxidant,such as hydrogen peroxide. However, such methods require extensiveagitation times in order to sufficiently oxidize the hydrocarbons in theslurry.

U.S. Pat. No. 6,576,145 and U.S. Patent Application Publication Nos.2004/0129646, 2004/0222164, and 2006/0104157 describe methods thatinvolve combining an aqueous slurry with an oxidizing agent, such ashydrogen peroxide, heating the resulting mixture to up to 80° C., andthen agitating the mixture in a linear oxidation vessel. The linearoxidation vessel is a long tube that is “P” shaped and comprises aplurality of rotary mixing devices disposed along the length of the tubeto actively agitate the mixture as it flows through the tube. However,such methods require the input of energy in order to activate the rotarymixing devices and very long tubes are required in order to providesufficient agitation to oxidize the hydrocarbons to the necessaryextent. Additionally, the rotary mixers cause froth to develop in themixture while it resides in the linear oxidation vessel.

Accordingly, there is a need for alternative technologies to overcome ormitigate at least some of the deficiencies of the prior art.

SUMMARY OF THE INVENTION

In accordance with an aspect, there is provided a method for recoveringhydrocarbons from an aqueous hydrocarbonaceous slurry, the methodcomprising:

-   -   pumping a mixture of the slurry and an oxidizing agent through a        conduit, wherein the conduit comprises a plurality of stationary        interior projections defining a non-linear path through the        conduit, and thereby agitating the mixture to release the        hydrocarbons from the slurry; and    -   separating the hydrocarbons from the slurry.

In an aspect, the method further comprises mixing the slurry and theoxidizing agent together in a reactor to form the mixture, prior topumping the mixture through the conduit.

In an aspect, the method further comprises heating the mixture to atemperature of from about 50° C. to about 100° C. in the reactor.

In an aspect, the temperature is from about 80° C. to about 100° C.

In an aspect, the temperature is from about 85° C. to about 90° C.

In an aspect, the temperature is about 85° C.

In an aspect, the temperature does not exceed about 85° C.

In an aspect, the method further comprises treating the mixture with apH-correcting agent.

In an aspect, the pH-correcting agent is selected from the groupconsisting of calcium oxide, calcium hydroxide, calcium carbonate,hydrochloric acid, carbon dioxide, and combinations thereof.

In an aspect, the method further comprises agitating and heating thehydrocarbonaceous slurry in a slurry hopper.

In an aspect, the hydrocarbonaceous slurry is heated to a temperature offrom about 50° C. to about 90° C. in the slurry hopper.

In an aspect, the hydrocarbonaceous slurry is derived from a bituminousor kerogenous source.

In an aspect, the bituminous or kerogenous source is selected from thegroup consisting of tar, tar sands, oil shales, oil sandstones, lignite,roof shingles, asphalt, oil refinery waste, organic contaminatedmaterials, industrial sludge, metal turnings coated in cutting-oil frommetal machining and manufacture processes, and combinations thereof.

In an aspect, particles in the hydrocarbonaceous slurry have a diameterof less than about 2 mm.

In an aspect, the method further comprises mixing water with ahydrocarbonaceous feedstock to produce the hydrocarbonaceous slurry.

In an aspect, the water and feedstock are mixed in a weight proportionof water to feedstock solids of from about 2:1 to about 1:1.

In an aspect, the weight proportion of water to feedstock solids isabout 2:1.

In an aspect, froth formation is suppressed in the conduit.

In an aspect, negligible froth is produced in the conduit.

In an aspect, the projections are baffles that project into the bore ofthe conduit from alternating walls of the conduit.

In an aspect, the oxidizing agent is selected from the group consistingof hydrogen peroxide, potassium permanganate, sodium peroxide, andcombinations thereof.

In an aspect, the oxidizing agent is hydrogen peroxide.

In an aspect, the oxidizing agent is used in an amount of between about0.1% to about 10% in water phase by weight.

In an aspect, the oxidizing agent is used in an amount of about 5% inwater phase by weight.

In an aspect, the conduit is parallel to the ground or has a positive ornegative slope with respect to the ground.

In an aspect, the conduit is parallel to the ground.

In an aspect, separating the hydrocarbons from the slurry comprisespumping the mixture into a separator to separate the oil phase from theaqueous and solid phases and to allow any large solids to separategravitationally for discharge.

In an aspect, the separator is an American Petroleum Institute (API)separator.

In an aspect, the method further comprises pumping the slurry into aweir, for heating and agitating the slurry and thereby furtherseparating the slurry into an aqueous layer, a layer comprising cleanedsolids that are substantially freed of hydrocarbons, and an oil layerthat forms a froth and contains the hydrocarbons.

In an aspect, the method further comprises collecting the froth andpumping the froth into an oil separator.

In an aspect, the aqueous layer is recycled for use in mixing with asubsequent feedstock batch for forming a subsequent batch of the aqueoushydrocarbonaceous slurry.

In an aspect, off-gas produced in the weir is recovered and used as aheat source in the method.

In an aspect, the method further comprises mixing the froth with acutter stock to further separate the froth into a second aqueous phase,an organic phase comprising the hydrocarbons, and further solidtailings.

In an aspect, the second aqueous, the organic phase, and the furthersolid tailings are separated in a centrifuge.

In an aspect, the method further comprises distilling the cutter stockfrom the organic phase for recycling.

In an aspect, the method further comprises sending the organic phase toan oil refinery for further processing.

In an aspect, the method further comprises separating remaining solidsfrom the hydrocarbonaceous slurry.

In an aspect, the solids comprise less than about 1% hydrocarbons.

In accordance with another aspect, there is provided a system forrecovering hydrocarbons from an aqueous hydrocarbonaceous slurry, thesystem comprising:

-   -   a mixing zone for mixing the slurry with an oxidizing agent to        form a mixture;    -   a conduit comprising a first end, a second end, and a plurality        of stationary interior projections defining a non-linear path        therebetween, the first end of said conduit operably connected        to the mixing zone for receiving the mixture; and    -   a separation zone, operably connected to the second end of said        conduit, for separating the hydrocarbons from the aqueous        slurry.

In an aspect, the mixing zone comprises a reactor for mixing the slurryand the oxidizing agent together to form the mixture.

In an aspect, the reactor is adapted to heat the mixture to atemperature of from about 50° C. to about 100° C.

In an aspect, the temperature is from about 80° C. to about 100° C.

In an aspect, the temperature is from about 85° C. to about 90° C.

In an aspect, the temperature is about 85° C.

In an aspect, the temperature does not exceed about 85° C.

In an aspect, the system further comprises a pH-correcting agent fortreating the mixture.

In an aspect, the pH-correcting agent is selected from the groupconsisting of calcium oxide, calcium hydroxide, calcium carbonate,hydrochloric acid, carbon dioxide, and combinations thereof.

In an aspect, the mixing zone further comprises a slurry hopper foragitating and heating the hydrocarbonaceous slurry.

In an aspect, the slurry hopper is adapted to heat the hydrocarbonaceousslurry to a temperature of from about 50° C. to about 90° C.

In an aspect, the hydrocarbonaceous slurry is derived from a bituminousor kerogenous source.

In an aspect, the bituminous or kerogenous source is selected from thegroup consisting of tar, tar sands, oil shales, oil sandstones, lignite,roof shingles, asphalt, oil refinery waste, organic contaminatedmaterials, industrial sludge, metal turnings coated in cutting-oil frommetal machining and manufacture processes, and combinations thereof.

In an aspect, particles in the hydrocarbonaceous slurry have a diameterof less than about 2 mm.

In an aspect, water is mixed with a hydrocarbonaceous feedstock toproduce the hydrocarbonaceous slurry.

In an aspect, water and feedstock are mixed in a weight proportion ofwater to feedstock solids of from about 2:1 to about 1:1.

In an aspect, the weight proportion of water to feedstock solids isabout 2:1.

In an aspect, froth formation is suppressed in the conduit.

In an aspect, negligible froth is produced in the conduit.

In an aspect, the projections are baffles that project into the bore ofthe conduit from alternating walls of the conduit.

In an aspect, the oxidizing agent is selected from the group consistingof hydrogen peroxide, potassium permanganate, sodium peroxide, andcombinations thereof.

In an aspect, the oxidizing agent is hydrogen peroxide.

In an aspect, the oxidizing agent is used in an amount of between about0.1% to about 10% in water phase by weight.

In an aspect, the oxidizing agent is used in an amount of about 5% inwater phase by weight.

In an aspect, the conduit is parallel to the ground or has a positive ornegative slope with respect to the ground.

In an aspect, the conduit is parallel to the ground.

In an aspect, the separation zone comprises a separator to separate theoil phase from the aqueous and solid phases and to allow any largesolids to separate gravitationally for discharge.

In an aspect, the separator is an American Petroleum Institute (API)separator.

In an aspect, the separation zone further comprises a weir, for heatingand agitating the slurry and thereby further separating the slurry intoan aqueous layer, a layer comprising cleaned solids that aresubstantially freed of hydrocarbons, and an oil layer that forms a frothand contains the hydrocarbons.

In an aspect, the system further comprises an oil separator forreceiving and separating the froth.

In an aspect, the aqueous layer is recycled for use in mixing with asubsequent feedstock batch for forming a subsequent batch of the aqueoushydrocarbonaceous slurry.

In an aspect, off-gas produced in the weir is recovered and used as aheat source for the system.

In an aspect, the system further comprises a cutter stock for mixingwith the froth to further separate the froth into a second aqueousphase, an organic phase comprising the hydrocarbons, and further solidtailings.

In an aspect, the separation zone further comprises a centrifuge, inwhich the second aqueous, the organic phase, and the further solidtailings are separated.

In an aspect, the cutter stock is distilled from the organic phase forrecycling.

In an aspect, the organic phase is sent to an oil refinery for furtherprocessing.

In an aspect, any remaining solids are separated from thehydrocarbonaceous slurry.

In an aspect, the solids comprise less than about 1% hydrocarbons.

In accordance with another aspect, there is provided a method forrecovering hydrocarbons from an aqueous hydrocarbonaceous slurry, themethod comprising:

-   -   mixing the slurry with an oxidizing agent at a temperature of        from about 80° C. to about 100° C. to form a mixture and thereby        release the hydrocarbons from the slurry; and    -   separating the hydrocarbons from the slurry.

In an aspect, the method further comprises pumping the mixture through aconduit, wherein the conduit comprises a plurality of stationaryinterior projections defining a non-linear path through the conduit, andthereby agitating the mixture to release the hydrocarbons from theslurry.

In an aspect, the method further comprises mixing the slurry and theoxidizing agent together in a reactor to form the mixture, prior topumping the mixture through the conduit.

In an aspect, the mixture is heated in the reactor.

In an aspect, the temperature is from about 85° C. to about 90° C.

In an aspect, the temperature is about 85° C.

In an aspect, the temperature does not exceed about 85° C.

In an aspect, the method further comprises treating the mixture with apH-correcting agent.

In an aspect, the pH-correcting agent is selected from the groupconsisting of calcium oxide, calcium hydroxide, calcium carbonate,hydrochloric acid, carbon dioxide, and combinations thereof.

In an aspect, the method further comprises agitating and heating thehydrocarbonaceous slurry in a slurry hopper.

In an aspect, the hydrocarbonaceous slurry is heated to a temperature offrom about 50° C. to about 90° C. in the slurry hopper.

In an aspect, the hydrocarbonaceous slurry is derived from a bituminousor kerogenous source.

In an aspect, the bituminous or kerogenous source is selected from thegroup consisting of tar, tar sands, oil shales, oil sandstones, lignite,roof shingles, asphalt, oil refinery waste, organic contaminatedmaterials, industrial sludge, metal turnings coated in cutting-oil frommetal machining and manufacture processes, and combinations thereof.

In an aspect, particles in the hydrocarbonaceous slurry have a diameterof less than about 2 mm.

In an aspect, the method further comprises mixing water with ahydrocarbonaceous feedstock to produce the hydrocarbonaceous slurry.

In an aspect, the water and feedstock are mixed in a weight proportionof water to feedstock solids of from about 2:1 to about 1:1.

In an aspect, the weight proportion of water to feedstock solids isabout 2:1.

In an aspect, froth formation is suppressed in the conduit.

In an aspect, negligible froth is produced in the conduit.

In an aspect, the projections are baffles that project into the bore ofthe conduit from alternating walls of the conduit.

In an aspect, the oxidizing agent is selected from the group consistingof hydrogen peroxide, potassium permanganate, sodium peroxide, andcombinations thereof.

In an aspect, the oxidizing agent is hydrogen peroxide.

In an aspect, the oxidizing agent is used in an amount of between about0.1% to about 10% in water phase by weight.

In an aspect, the oxidizing agent is used in an amount of about 5% inwater phase by weight.

In an aspect, the conduit is parallel to the ground or has a positive ornegative slope with respect to the ground.

In an aspect, the conduit is parallel to the ground.

In an aspect, separating the hydrocarbons from the slurry comprisespumping the mixture into a separator to separate the oil phase from theaqueous and solid phases and to allow any large solids to separategravitationally for discharge.

In an aspect, the separator is an American Petroleum Institute (API)separator.

In an aspect, the method further comprises pumping the slurry into aweir, for heating and agitating the slurry and thereby furtherseparating the slurry into an aqueous layer, a layer comprising cleanedsolids that are substantially freed of hydrocarbons, and an oil layerthat forms a froth and contains the hydrocarbons.

In an aspect, the method further comprises collecting the froth andpumping the froth into an oil separator.

In an aspect, the aqueous layer is recycled for use in mixing with asubsequent feedstock batch for forming a subsequent batch of the aqueoushydrocarbonaceous slurry.

In an aspect, off-gas produced in the weir is recovered and used as aheat source in the method.

In an aspect, the method further comprising mixing the froth with acutter stock to further separate the froth into a second aqueous phase,an organic phase comprising the hydrocarbons, and further solidtailings.

In an aspect, the second aqueous, the organic phase, and the furthersolid tailings are separated in a centrifuge.

In an aspect, the method further comprises distilling the cutter stockfrom the organic phase for recycling.

In an aspect, the method further comprises sending the organic phase toan oil refinery for further processing.

In an aspect, the method further comprises separating remaining solidsfrom the hydrocarbonaceous slurry.

In an aspect, the solids comprise less than about 1% hydrocarbons.

Other features and advantages of the present invention will becomeapparent from the following detailed description. It should beunderstood, however, that the detailed description and the specificexamples while indicating embodiments of the invention are given by wayof illustration only, since various changes and modifications within thespirit and scope of the invention will become apparent to those skilledin the art from said detailed description.

DESCRIPTION OF THE FIGURES

The present invention will be further understood from the followingdescription with reference to the Figures, in which:

FIG. 1 shows a schematic view of system described herein; and

FIG. 2 shows a cross-sectional view of a conduit used in the system ofFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A system and method for recovering hydrocarbons from an aqueoushydrocarbonaceous slurry is provided. The hydrocarbonaceous material maybe derived from any bituminous or kerogenous source, such as tar, tarsands, oil shales, oil sandstones, lignite, roof shingles, asphalt, oilrefinery waste, organic contaminated materials, industrial sludge, andmetal turnings coated in cutting-oil from metal machining andmanufacture processes, for example.

Turning to FIG. 1, a hydrocarbonaceous material is mined, crushed,ground, comminuted, screened, or otherwise pre-treated so as toeliminate large rocks and debris and to yield a feedstock 100 having asand-like particle size of less than about 2 mm in diameter. Water 102is mixed with the feedstock 100 in a mixing zone 103. The mixing zone103 includes a slurry hopper 104 that forms a pumpable, aqueous,hydrocarbonaceous slurry 106 from the feedstock 100 and water 102. Theslurry 106 has a weight percent proportion of water 102 to feedstock 100of between about 2:1 and about 1:1, typically about 2:1.

The slurry 106 is conditioned by agitation and heating in the slurryhopper 104 to a temperature of between about 50° C. and about 90° C. torelease free hydrocarbons, melt waxy hydrocarbon solids, reduce theviscosity of the batch, reduce the density of hydrocarbon fractionswithin the batch, and begin to break surface adhesion of hydrocarboncompounds bound to substrate surfaces. The free hydrocarbons thusreleased define a first hydrocarbon residue.

The slurry 106 is then pumped into a reactor 108, where it is heated toabout 85° C. and is treated with a pH-correcting agent 110, such ascalcium oxide, calcium hydroxide, calcium carbonate, hydrochloric acid,or carbon dioxide, for example, if necessary. The slurry 106 is thenblended with an oxidizing agent 112, such as hydrogen peroxide, in anamount of between about 0.1% and about 10.0%, typically about 5%, inwater phase by weight.

Although the reaction will proceed within the temperature range ofbetween about 50° C. and about 100° C., temperature studies have shownthat heating above 85° C. does not substantially increase hydrocarbonoutput volume yield. Without wishing to be restrained by theory, it isbelieved that the slurry 106, having been heated to about 85° C. andthen mixed with the oxidizing agent 112 becoming mixture 107, undergoesan exothermic reaction that raises the reaction temperature to about 90°C. This exothermic reaction advantageously perpetuates the reactionbetween the slurry 106 and the oxidizing agent 112 within the mixture107 without the additional input of heat from a secondary source.Additionally, the temperature of about 85° C. is advantageous because itprovides for better release of viscous long-chain hydrocarbons fromparticle substrates. Heating to higher temperatures, such as 100° C.,would also increase the water vapour component content in off-gas andwould liberate more semi-volatile hydrocarbon components in the off-gasas well. Thus, the use of about 85° C. as the reaction temperature inthe reactor 108 is surprisingly energy efficient and improves yield,without releasing excess water or hydrocarbon components in the off-gas.

The slurry 106 and oxidizing agent 112 mixture 107 is then pumped into aconduit 114 that includes a plurality of interior projections 116 thatcollectively define a non-linear path 118 through which the mixture 107flows. As shown in FIG. 2, the projections 116 are formed as baffles 120that project from alternating walls of the conduit 114. Advantageously,the projections 116 are stationary, meaning that they do not move orrotate. In this way, the mixture 107 is passively agitated simply byvirtue of its flow through the non-linear path 118 within the conduit114. This is beneficial because a reduced number of moving parts reduceschances of parts breaking or sticking and stopping production.Additionally, the technology is considered more environmentally friendlybecause no input of energy is required in order to cause agitation,since the agitation is passive rather than active.

Moreover, mixing in the conduit 114 described herein provides forimproved mixing for a wide range of substrate particle sizes derivedfrom the large variety of ore species, from micron-sized oil-shaleparticles to centimeter-sized gravel contained in asphalt, for example.The violent mixing caused by the projections 116 within the conduit 114advantageously increases the number of times the substrate particles canbe exposed to fresh oxidant, improving and it provides a method ofsuppressing formation of froth too early during the reaction of theslurry 106 with the oxidizing agent 112. Froth is produced when oxygenmixes with the slurry 106 and chemically attaches to the hydrocarbonmolecules in the slurry 106. When this happens, the long-chainhydrocarbons cleave and float to the surface in a froth layer. It isimportant to prevent premature froth formation because the froth layerwill trap solid fine particulates and prevent any further reactionbetween the particulates and the oxidizing agent 112 by effectivelyisolating the particulates in the froth. Advantageously, use of theconduit 114 described herein keeps the fines substantially suspended inthe slurry 106 and oxidizing agent 112 mixture 107 for the duration ofthe reaction time, that is, the duration of the time that the mixture isspent in the conduit 114.

In the presence of heat and an oxidizing agent, the electrostaticallybound hydrocarbons are released from the surface of particles within theslurry, especially very fine particles. The bound hydrocarbons thusreleased define a second hydrocarbon residue.

Without wishing to be bound by theory, it is believed that when themicroscopic hydrocarbon-coated rock substrate particles within thefeedstock 100 are suspended in a slurry 106, charged with the oxidizingagent 112, and transported through the non-linear path 118 within theconduit 114, the colloidal and interfacial reaction between theoxidizing agent and the particles may be explained at the microscopiclevel for particles that measure equal to or less than 10 μm in diameterby applying Formula I:

$\begin{matrix}{\xi = \frac{4\; \pi \; {Qd}}{D}} & (I)\end{matrix}$

to calculate the ζ-potential, where Q=the charge per unit area;d=distance from the particle surface as the thickness of the Gegenionlayer; and D=the dielectric constant of the layer.

Also without wishing to be bound by theory, it is believed that the heatand oxidizing agent also function to oxidize allyl and other hydrocarbonmoieties to lighter petroleum fractions via Fenton's reaction. Hydrogenperoxide reacts with ubiquitous ferrous ions to produce a hydroxylradical in an acidified aqueous medium, in accordance with Formula (II):

H₂O₂+Fe²⁺→OH.+OH⁻+Fe³⁺  (II)

The resultant hydroxyl free radicals (OH.) are extremely powerfuloxidizers that progressively react with organic compounds through aseries of oxidation reactions. During the process, the oxidationreactions proceed according to Formula (III) by degrading the organicconstituents (b) having long chain lengths (n carbon atoms) into agreater number of molecules (b+c) having less complex and shorter carbonchain lengths (n-a):

H₂O₂ +bC_(n)H_(x)→H₂O+(b+c)C_(n-a)H_(x)+½O₂  (III)

In an excess of oxidizing agent, all organic carbon may be converted toCO₂ in accordance with Formula (IV) (not balanced):

H₂O₂+C_(n)H_(x)→H₂O+nCO₂  (IV)

However, in the process described herein, wherein reaction time,temperature, and the amount of oxidant may be precisely controlled by aprogrammable controller, Fenton's reaction is limited to breakingrelatively few covalent bonds, sufficient only to reduce the averagemolecular weight of the very large molecular weight bituminous orkerogenic long-chain hydrocarbons that were the starting point, to thoseof the shorter-chain hydrocarbons found in the first and second residueschemically characterized as being similar to that of conventional crudeoil produced from a well. Such shorter-chain hydrocarbons could then beprocessed in the same manner as crude oil is conventionally processedand can be sent to an oil refinery for distillation processing.

In one example of further processing, after mixture 107 is pumpedthrough conduit 114, it reaches a separation zone 122, where thehydrocarbons are separated from the slurry 106 in the mixture 107.First, the mixture 107 is pumped into a separator 124, such as anAmerican Petroleum Institute (API) separator, where the oil phase beginsto separate from the aqueous and solid phases and any larger solidsseparate gravitationally and are discharged.

The mixture 107 then reaches a weir 126, which heats and agitates themixture 107 and encourages the mixture 107 to further separate into: 1)an aqueous layer; 2) cleaned solids that settle to the bottom and aresubstantially freed of hydrocarbons; and 3) hydrocarbons that separatefrom the aqueous layer as they coalesce and float to the top of the weirto form an oil layer or froth 128, which is rich in first and secondhydrocarbon residues. The froth 128 typically contains substantialamounts of entrained water and fines. For process efficiency, as shownin FIG. 1, generation of the next batch is permitted in reactor 108while froth 128 is being further processed (semi-continuous, or movingbatch process).

The froth 128 then spills over the weir 126 and into a collecting trough130 surrounding the weir 126 and is then pumped into an oil separator132. Water from the weir 126 is recycled back to the slurry hopper 104as water 102. The weir 126 may optionally be configured so as to allowcapture of the off-gas 134 produced during this stage. Optional vacuumrecovery of off-gas 134 that develops would provide compressed gas tofuel a boiler and provide heat for the process system as this off-gas134 is oxygenated and results in clean burning fuel.

To remove water and fines from the froth 128, the froth 128 containingoxidized and non-oxidized bitumen and/or kerogen is mixed, typically ata ratio of 1:1, with a “cutter stock” 136 (typically either diesel oilor naphtha), to dilute and solubilize the bitumen or kerogen, causing afurther separation of the froth 128 into a second aqueous phasecontaining the fines and an organic phase containing the hydrocarbons.In some operations, this separation may be effected by discharging theblended froth 128 through a commercial centrifuge 138, from which thesolid tailings from the aqueous phase may be landfilled directly.Typically, the hydrocarbon content of the combined first and secondtailings, from the weir 126 and the oil separator 132, respectively, isless than about 1%, which meets the requirements for disposal inaccordance with government regulations.

The reclaimed organic phase 140 may be subjected to distillation toremove and recover cutter stock 136 for recycling. The reclaimed organicphase 140, containing partially-oxidized bitumen and/or kerogenrecovered by the subject process and free of the residual water and fineparticulates which characterize hydrocarbon residues produced by theknown art processes, now may be sent for further processing such as toan oil refinery.

It has been described above that the slurry 106 is pumped into reactor108 and heated to about 85° C. It will be understood that a range oftemperatures could be used, such as for about 50° C. to about 100° C.,from about 80° C. to about 100° C., or from about 85° C. to about 90° C.However, a temperature of 85° C. is advantageous because it results in amore energy efficient process with improved yields, as has beendescribed above. Thus, in an aspect, the temperature to which the slurry106 is actively heated in the reactor 108 does not exceed about 85° C.

The oxidizing agent 112 has been described above as being hydrogenperoxide, however it will be understood that any oxidizing agent couldbe used, such as, for example, potassium permanganate or sodiumperoxide. Hydrogen peroxide is advantageous because it ultimatelydecomposes into water and oxygen, leaving no elemental or mineralresidue in the tailings.

The projections 116 have been described above as baffles 120 thatproject from alternating walls of the conduit 114. However, it will beunderstood that the baffles 120 could project from the walls of theconduit 114 in other ways and still provide a non-linear path 118through the conduit 114. For example, while FIG. 2 shows the baffles 120alternating in pairs along the cross-section of the conduit 114,extending from two different surfaces of the conduit 114, the baffles120 could instead alternate in triplets and extend from three differentsurfaces of the conduit 114. Moreover, the shape, spacing, and/or angelof projection from the conduit 114 wall of the baffles 120 could bevaried to increase or decrease non-linear flow as would be understood bya skilled person. Additionally, stationary projections 116 other thanbaffles 120 that collectively define a non-linear path 118 through whichthe mixture 107 of slurry 106 and oxidizing agent 112 flows arecontemplated. For example, the projections could resemble a number offingers that disrupt the linear flow of the mixture.

While the conduit 114 defines a non-linear path 118 through its bore,the conduit 114 itself may be linear or non-linear but is, in an aspect,linear. It will be understood that the length of the conduit 114 isdetermined by the required residence time of the mixture 107 of theoxidizing agent 112 and the slurry 106 to sufficiently oxidize thehydrocarbons in the mixture 107 and thereby strip them from the solidsubstrates to which they are attached. The conduit 114 is typicallysubstantially parallel to the ground, such that the mixture 107 does notflow substantially on its own but must be pumped. However, it will beunderstood that the conduit 114 could be positioned at any angle to theground in a positive or negative slope direction, as long as sufficientagitation of the mixture is provided to oxidize the hydrocarbons to thenecessary degree.

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Finally, terms of degree such as “substantially”, “about”and “approximately” as used herein mean a reasonable amount of deviationof the modified term such that the end result is not significantlychanged. These terms of degree should be construed as including adeviation of at least ±5% of the modified term if this deviation wouldnot negate the meaning of the word it modifies.

The above disclosure generally describes the present invention. Althoughspecific terms have been employed herein, such terms are intended in adescriptive sense and not for purposes of limitation.

All publications, patents and patent applications are hereinincorporated by reference in their entirety to the same extent as ifeach individual publication, patent or patent application wasspecifically and individually indicated to be incorporated by referencein its entirety.

Although preferred embodiments of the invention have been describedherein in detail, it will be understood by those skilled in the art thatvariations may be made thereto without departing from the spirit of theinvention or the scope of the appended claims.

What is claimed is:
 1. A method for recovering hydrocarbons from anaqueous hydrocarbonaceous slurry, the method comprising: pumping amixture of the slurry and an oxidizing agent through a conduit, whereinthe conduit comprises a plurality of stationary interior projectionsdefining a non-linear path through the conduit, and thereby agitatingthe mixture to release the hydrocarbons from the slurry; and separatingthe hydrocarbons from the slurry.
 2. The method of claim 1, furthercomprising mixing the slurry and the oxidizing agent together in areactor to form the mixture, prior to pumping the mixture through theconduit.
 3. The method of claim 2, further comprising heating themixture to a temperature of from about 50° C. to about 100° C. in thereactor.
 4. The method of claim 3, wherein the temperature is about 85°C.
 5. The method of claim 1, further comprising treating the mixturewith a pH-correcting agent selected from the group consisting of calciumoxide, calcium hydroxide, calcium carbonate, hydrochloric acid, carbondioxide, and combinations thereof.
 6. The method of claim 1, furthercomprising agitating and heating the hydrocarbonaceous slurry in aslurry hopper to a temperature of from about 50° C. to about 90° C. 7.The method of claim 1, wherein particles in the hydrocarbonaceous slurryhave a diameter of less than about 2 mm.
 8. The method of claim 1,further comprising mixing water with a hydrocarbonaceous feedstock toproduce the hydrocarbonaceous slurry, wherein the water and feedstockare mixed in a weight proportion of water to feedstock solids of fromabout 2:1 to about 1:1.
 9. The method of claim 1, wherein negligiblefroth is produced in the conduit.
 10. The method of claim 1, wherein theprojections are baffles that project into the bore of the conduit fromalternating walls of the conduit.
 11. The method of claim 1, wherein theoxidizing agent is selected from the group consisting of hydrogenperoxide, potassium permanganate, sodium peroxide, and combinationsthereof.
 12. The method of claim 1, wherein the oxidizing agent is usedin an amount of between about 0.1% to about 10% in water phase byweight.
 13. The method of claim 1, wherein the conduit is parallel tothe ground.
 14. The method of claim 1, further comprising separatingremaining solids from the hydrocarbonaceous slurry, wherein the solidscomprise less than about 1% hydrocarbons.
 15. A method for recoveringhydrocarbons from an aqueous hydrocarbonaceous slurry, the methodcomprising: mixing the slurry with an oxidizing agent at a temperatureof from about 80° C. to about 100° C. to form a mixture and therebyrelease the hydrocarbons from the slurry; and separating thehydrocarbons from the slurry.
 16. The method of claim 15, furthercomprising pumping the mixture through a conduit, wherein the conduitcomprises a plurality of stationary interior projections defining anon-linear path through the conduit, and thereby agitating the mixtureto release the hydrocarbons from the slurry.
 17. The method of claim 15,further comprising mixing the slurry and the oxidizing agent together ina reactor to form the mixture, prior to pumping the mixture through theconduit.